To omit such changes if you choose open the omitproplist.txt file in AD Change Reporter installation directory and modify the following string:
#*.servicePrincipalName to *.servicePrincipalName
(just remove #)

Also in the unomitproplist.txt file change *.servicePrincipalName to #*.servicePrincipalName
(just add #)

Nightly, I receive the same email/notification as the OP for two of my SQL servers. I suspect the notifications are generated due to the nightly scheduled GFS backup, but there are 50 other virtual servers sever in my pool, 10 of which are also SQL servers, but Netwrix doesn't send notifications for any of the other VMs.
I don't know if this info helps the OP, but I suspect it's an issue with a service on both of the offending SQL VMs.